Biodegradable biomaterials in orthopedic surgery: A narrative review of the current evidence

BACKGROUND

Biomaterials are routinely used in orthopedic surgery to fill bone defects, improve bone healing, and as degradable fixation material. A wide range of materials are currently in use, and the materials are chosen according to their bioactive properties. Osteoinductive materials stimulate bone healing by promoting osteogenesis. Osteoconductive materials facilitate bone growth on the surface of the material. Despite the many materials in use and an increasing number of published studies, randomized controlled trials on the subject are scarce.

METHODS

This review aims to summarize the history of biodegradable biomaterials and also the published level I evidence currently available on orthopedic biomaterials.

RESULTS

Most of the studies have been superiority trials with non-significant differences compared to conventional treatment options, confirming that several biomaterials are suitable treatment options for multiple indications including bone and/or tendon fixation, filling bone defects, and spinal fusion. Biomaterials help to avoid donor site complications associated with autogenous bone grafts and often eliminate the need for implant removal. However, the surgical technique may in some cases be more demanding than with conventional methods. Careful consideration of the pros and cons is therefore recommended in clinical practice.

CONCLUSION

Biodegradable biomaterials complement the range of available treatment options in several fields of orthopedic surgery. However, some biomaterials performed worse than expected and were not recommended for clinical use, emphasizing the need for high-quality randomized trials. It is also noteworthy that several trials included only a limited number of patients, rendering the interpretation of the results of these underpowered studies challenging.

Outcome and survival of surgically treated acute subdural hematomas and postcraniotomy hematomas - A retrospective cohort study

Background

The morbidity and mortality of acute subdural hematoma (aSDH) remains high. Several factors have been reported to affect the outcome and survival of these patients. In this study, we explored factors potentially associated with the outcome and survival of surgically treated acute subdural hematoma (aSDH), including postcraniotomy hematomas (PCHs).

Methods

This retrospective cohort study was conducted in a single tertiary university hospital between 2008 and 2012 and all aSDH patients that underwent surgical intervention were included. A total of 132 cases were identified for collection of demographics, clinical, laboratory, and imaging data. Univariate and multivariable analyses were performed to assess factors associated with three-month Glasgow Outcome Scale (GOS) and survival at one- and five-year.

Results

In this study, PCH (n = 14, 10.6%) was not associated with a worse outcome according to the 3- month GOS (p = 0.37) or one (p = 0.34) and five-year (p = 0.37) survival. The multivariable analysis showed that the volume of initial hematoma (p = 0.009) and Abbreviated Injury Scale score (p = 0.016) were independent predictors of the three-month GOS. Glasgow Coma Scale (GCS) score (p < 0.001 and p = 0.037) and age (p = 0.048 and p = 0.003) were predictors for one and five-year survival, while use of antiplatelet drug (p = 0.030), neuroworsening (p = 0.005) and smoking (p = 0.026) were significant factors impacting one year survival. In addition, blood alcohol level on admission was a predictor for five-year survival (p = 0.025).

Conclusions

These elucidations underscore that, although PCHs are pertinent, a comprehensive appreciation of multifarious variables is indispensable in aSDH prognosis. These findings are observational, not causal. Expanded research endeavors are advocated to corroborate these insights.

Association Between Lenke Classification, The Extent of Lumbar Spinal Fusion, and Health-Related Quality of Life After Instrumented Spinal Fusion for Adolescent Idiopathic Scoliosis

STUDY DESIGN

Prospective cohort study.

SUMMARY OF BACKGROUND DATA

Lenke classification is used to define the curve type in adolescent idiopathic scoliosis (AIS). The association of Lenke classification and long-term postoperative health-related quality of life (HRQoL) remains unclear.

OBJECTIVE

The purpose of this study was to assess the association between Lenke classification and HRQoL in patients who underwent spinal fusion for AIS.

MATERIALS AND METHODS

In all, 146 consecutive patients (mean age 15.1 yr) operated for AIS between 2007 and 2019 with a minimum 2-year follow-up were included. Fifty-three (36%) patients reached the 10-year follow-up. Their HRQoL was assessed with the SRS-24 questionnaire preoperatively, at six months, two years, and 10 years after surgery.

RESULTS

The preoperative major curve was the largest in Lenke 3 (mean 63 ° ) and 4 (mean 62 ° ) groups and the lowest in Lenke 5 groups (mean 48 ° , P <0.05). These curves were corrected to a mean of 15 ° with no differences between groups. We found no evidence of differences between the preoperative HRQoL scores between the Lenke groups. The self-image domain of SRS-24 was lower in patients with isolated major thoracolumbar scoliosis (Lenke 5) when compared with double-thoracic (Lenke 2) group at the two-year follow-up (mean [95% CI] 3.6 [3.3-3.9] vs. 4.3 [4.1-4.6]). The postoperative satisfaction domain was lower in Lenke 5 group when compared with main thoracic (Lenke 1) group (mean [95% CI] 3.8 [3.5-4.0] vs. 4.3 [4.2-4.5]) and Lenke 2 group (mean 4.4, 95% CI 4.2-4.6) at the two-year follow-up. The mean total score of SRS-24 at the 10-year follow-up was highest in Lenke 1 group (mean 4.06, 95% CI 3.79-4.33) and lowest in Lenke 6 group (mean 2.92, 95% CI 2.22-3.61).

CONCLUSIONS

Lenke classification and especially its curve type (major thoracic vs. major thoracolumbar scoliosis) was associated with long-term health-related quality of life after instrumented spinal fusion for AIS.

Traumatic Hip Dislocation in Pediatric Patients: Clinical Case Series and a Narrative Review of the Literature with an Emphasis on Primary and Long-Term Complications

Traumatic hip dislocation is a rare injury in pediatric populations. Dislocation may be associated with low-energy trauma, such as a minor fall. Traumatic hip dislocation is associated with severe complications, such as avascular necrosis of the femoral head. Timely diagnosis and reposition decrease the rate of complications. In this study we retrospectively assessed traumatic hip dislocations in pediatric patients during a 10-year timespan in a university hospital. There were eight cases of traumatic hip dislocations. All patients had a minimum follow-up of two years and were followed with MRI scans. One patient developed avascular necrosis during the follow-up which resolved conservatively. There were no other significant complications. In conclusion, traumatic hip dislocation is a rare injury which is associated with severe complications. Patients in our case series underwent a timely reposition. The complication rate was similar to previous reports.

Health-related quality of life outcomes in adolescent Scheuermann's kyphosis patients treated with posterior spinal fusion: A comparison with age- and sex-matched controls

PURPOSE

To assess the health-related quality of life and radiographic outcomes of surgically treated adolescent Scheuermann's kyphosis patients after minimum of 2-year follow-up and to compare the health-related quality of life with age- and sex-matched healthy controls.

METHODS

Twenty-two consecutive adolescents (mean age = 16.7 years) undergoing posterior spinal fusion for Scheuermann's kyphosis were included and matched by age and sex with two healthy controls. The health-related quality of life was evaluated using the Scoliosis Research Society-24 questionnaire. Radiographic parameters were measured for comparison preoperatively and at 6 months and 2-year follow-ups. The health-related quality of life parameters were compared with healthy controls at 2 years of follow-up.

RESULTS

The mean maximal thoracic kyphosis improved from 79° (range = 75°-90°) to 55° (range = 45°-75°) (p < 0.001), and the mean lumbar lordosis was reduced from 71° (range = 51°-107°) to 52° (range = 34°-68°) (p < 0.001) after 2 years postoperatively. Incidence of proximal junctional kyphosis (PJK) was 18%. The scores of the Scoliosis Research Society-24 improved, with statistical significance observed in pain and self-image domains from preoperative to 2-year follow-up (p = 0.002 in both domains). The self-image and function were significantly lower in the operated patients at their 2-year follow-up visit compared to controls (p = 0.023 for self-image and p < 0.001 for function).

CONCLUSION

Instrumented posterior spinal fusion improves the health-related quality of life of Scheuermann's kyphosis patients during the 2-year follow-up. The greatest improvement is observed in pain and self-image domains. The health-related quality of life in pain and activity domains reaches the level of healthy individuals, while function and self-image remain at a statistically lower level.

Intraoperative 3D Imaging Reduces Pedicle Screw Related Complications and Reoperations in Adolescents Undergoing Posterior Spinal Fusion for Idiopathic Scoliosis: A Retrospective Study

Widely used surgical treatment for adolescent idiopathic scoliosis (AIS) is posterior spinal fusion using pedicle screw instrumentation (PSI). Two-dimensional (2D) or three-dimensional (3D) navigation is used to track the screw positioning during surgery. In this study, we evaluated the screw misplacement, complications, and need for reoperations of intraoperative 3D as compared to 2D imaging in AIS patients. There were 198 adolescents, of which 101 (51%) were evaluated with 2D imaging and 97 (49%) with 3D imaging. Outcome parameters included radiographic correction, health-related quality of life (HRQOL), complications, and reoperations. The mean age was 15.5 (SD 2.1) years at the time of the surgery. Forty-four (45%) patients in the 3D group and 13 (13%) patients in the 2D group had at least one pedicle screw repositioned in the index operation (p < 0.001). Six (6%) patients in the 2D group, and none in the 3D group had a neurological complication (p = 0.015). Five (5%) patients in the 2D group and none in the 3D group required reoperation (p = 0.009). There were no significant differences in HRQOL score at two-year follow-up between the groups. In conclusion, intraoperative 3D imaging reduced pedicle screw-related complications and reoperations in AIS patients undergoing PSI as compared with 2D imaging.

Structural and Construct Validity of the Foot and Ankle Ability Measure (FAAM) With an Emphasis on Pain and Functionality After Foot Surgery: A Multicenter Study

The Foot and Ankle Ability Measure (FAAM) is a patient-reported outcome measure that is available in several languages. We aim to assess the structural and construct validity of the FAAM with an emphasis on pain and functionality after foot surgery. The activities of daily living (ADL) and Sports subscales of the Finnish version of the FAAM were completed by 182 patients who underwent operative treatment for disorders of the foot. Convergent validity was assessed by principal component analysis using Spearman's correlation coefficient between the FAAM subscales and the principal components (Function-PC and Pain-PC) derived from validated patient-reported outcome measures. Subscales were studied for floor and ceiling effects, internal consistency and unidimensionality. Internal consistency was examined with Cronbach's alpha and the subscale structure with exploratory factor analysis. FAAM-ADL had high correlation with the Function-PC (r = 0.87, 95% confidence interval [CI] 0.81-0.91) and the Pain-PC (r = 0.75, 95% CI 0.65-0.83). FAAM-Sports had moderate correlation (r = 0.64, 95% CI 0.50-0.74) with the Function-PC and high correlation (r = 0.74, 95% CI 0.64-0.82) with the Pain-PC. No floor or ceiling effects were observed. Cronbach's alpha was 0.97 (95% CI 0.96-0.98) for the ADL and 0.93 (95% CI 0.91-0.95) for the Sports subscales. The results supported the unidimensionality of the FAAM-Sports. Within the ADL subscale, 3 factors were identified, suggesting a 3-factor model for the FAAM overall. Results highlighted the inter-relationship of pain and physical function. Further research on longitudinal validity is needed.

Alcohol intoxication and lack of helmet use are common in electric scooter-related traumatic brain injuries: a consecutive patient series from a tertiary university hospital

PURPOSE

Clinicians have increasingly encountered traumatic brain injuries (TBI) related to electric scooter (ES) accidents. In this study, we aim to identify the modifiable risk factors for ES-related TBIs.

METHODS

A retrospective cohort of consecutive patients treated for ES-related traumatic brain injuries in a tertiary university hospital between May 2019 and September 2021 was identified and employed for the study. The characteristics of the accidents along with the clinical and imaging findings of the injuries were collected from the patient charts.

RESULTS

During the study period, 104 TBIs related to ES accidents were identified. There was a high occurrence of accidents late at night and on Saturdays. In four cases, the patient's helmet use was mentioned (3.8%). Seventy-four patients (71%) were intoxicated. At the scene of the accident, seventy-seven (74%) of the patients had a Glasgow Coma Scale score of 13-15, three patients (3%) had a score of 9-12, and two patients (2%) had a score of 3-8. The majority (83%) of TBIs were diagnosed as concussions. Eighteen patients had evidence of intracranial injuries in the imagining. Two patients required neurosurgical procedures. The estimated population standardized incidence increased from 7.0/100,000 (95% CI 3.5-11/100,000) in 2019 to 27/100,000 (95% CI 20-34/100,000) in 2021.

CONCLUSIONS

Alcohol intoxication and the lack of a helmet were common in TBIs caused by ES accidents. Most of the accidents occurred late at night. Targeting these modifiable factors could decrease the incidence of ES-related TBIs.

Structural validity of the foot and ankle outcome score for orthopaedic pathologies with Rasch Measurement Theory

BACKGROUND

The Foot and Ankle Outcome Score (FAOS) is one of the most frequently used patient-reported outcome measures for foot and ankle conditions. The aim is to test the structural validity of the Finnish version of the FAOS using Rasch Measurement Theory.

METHODS

FAOS scores were obtained from 218 consecutive patients who received operative treatment for foot and ankle conditions. The FAOS data were fitted into the Rasch model and person separation index (PSI) calculated.

RESULTS

All the five subscales provided good coverage and targeting. Three subscales presented unidimensional structure. Thirty-eight of the 42 items had ordered response category thresholds. Three of the 42 items had differential item functioning towards gender. All subscales showed sufficient fit to the Rasch model. PSI ranged from 0.73 to 0.94 for the subscales.

CONCLUSIONS

The Finnish version of the FAOS shows acceptable structural validity for assessing complaints in orthopaedic foot and ankle patients.

Longitudinal Validity and Minimal Important Change for the Modified Lower Extremity Functional Scale (LEFS) in Orthopedic Foot and Ankle Patients

The lower extremity functional scale (LEFS) is a patient-reported outcome measure for lower extremity disorders. Aim of this study was to assess the longitudinal validity including responsiveness and test-retest reliability of the revised 15-item version, and to define the minimal important change (MIC) of the modified LEFS in a generic sample of orthopedic foot and ankle patients who underwent surgery. Responsiveness, effect size, and standardized response mean were measured by determining the score change between the baseline and 6 months administration of the LEFS from 156 patients. There was no significant difference between preoperative (median 78, interquartile range [IQR] 64.2-90.3) and postoperative (median 75.0, IQR 61.7-95.0) scores. Both effect size and standardized response mean were low (0.06 and 0.06, respectively). Test-retest reliability of the LEFS was satisfactory. Intraclass correlation coefficient was 0.85 (95% confidence interval 0.81-0.88). MIC value could not be estimated due to the lack of significant score change. The modified LEFS presented with relatively low longitudinal validity in a cohort of generic orthopedic foot and ankle patients. The findings of this study indicate that the modified LEFS might not be the optimal instrument in assessing the clinical change over time for these patients.

Matched Comparison of Magnetically Controlled Growing Rods with Traditional Growing Rods in Severe Early-Onset Scoliosis of ≥90°: An Interim Report on Outcomes 2 Years After Treatment

BACKGROUND

Severe early-onset scoliosis (EOS) is managed surgically but represents a challenge due to limited implant fixation points, large curve size, and fragile patients with comorbidities. Magnetically controlled growing rods (MCGRs) have the advantage of avoiding surgical intervention for routine lengthening, but their ability to address severe EOS has not been studied, to our knowledge.

METHODS

A retrospective review of a prospectively collected international database identified 44 children with severe (≥90°) EOS treated with MCGRs who met our study criteria. Etiology, age, and sex-matched patients treated with traditional growing rods (TGRs) were identified from the same database. Patients were evaluated at a 2-year follow-up. No patients with vertically expandable prosthetic titanium ribs (VEPTRs) were included. The health-related quality of life was evaluated with the 24-Item Early Onset Scoliosis Questionnaire (EOSQ-24).

RESULTS

The mean preoperative major coronal curve was 104° in the MCGR group and 104° in the TGR group. At the 2-year follow-up, the mean major coronal curves were 52° and 66° (p = 0.001), respectively. The mean T1-T12 heights were 155 mm and 152 mm preoperatively and 202 mm and 192 mm at the 2-year follow-up (p = 0.088). According to Kaplan-Meier analysis, the 2-year unplanned-revision-free survival was 91% in the MCGR group and 71% in the TGR group (p < 0.005). The 2-year score in the EOSQ-24 pulmonary function domain was better in the MCGR group. There were no other significant differences in the EOSQ-24 scores between the groups.

CONCLUSIONS

MCGRs for severe EOS provided significantly better major curve correction with significantly fewer unplanned revisions than TGRs at a 2-year follow-up.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Minimal important change for Foot and Ankle Outcome Score (FAOS)

BACKGROUND

Although Foot and Ankle Outcome Score (FAOS) is a widely used patient-reported outcome measure (PROM) for foot and ankle conditions, research on its longitudinal validity is still needed. Minimal important change (MIC) values for the FAOS were determined using predictive modeling.

METHODS

Overall, 134 patients that underwent operative treatment for foot and ankle conditions were included. An anchor based predictive logistic modeling method was used for estimating the MIC values for the FAOS subscales after surgery.

RESULTS

Mean score changes in the improved and the unimproved groups were 17.7 and 0.43 points for Pain, 3.9 and -3.3 points for Symptoms, 21.3 and 1.8 points for Activities and daily living (ADL), 8.7 and -2.8 points for Sport, and 12.5 and -3.3 points for quality of life subscale, respectively. MIC was successfully determined to four out of five subgroups as follows: Pain 9.5 (94% CI -6.4 to 24.6); ADL 11.7 (95% CI -19.6 to 46.6); Sport (95% CI -10.4 to 15.4); QoL 5.0 (95% CI -2.6 to 12.9). The Symptoms subgroup presented with low MIC of 0.3 (95% CI -11.7 to 13.4) fitting to the measurement error.

CONCLUSION

ADL, Sports, Pain, and QoL subscales of the FAOS presented logical MIC values. The MIC can be further evaluated for specific conditions.

Results of Conservative and Surgical Management in Children with Idiopathic and Nonidiopathic Os Odontoideum

OBJECTIVE

The outcomes of conservative and operative treatment of os odontoideum in children remain unclear. Our objective was to study the outcomes of conservative and surgical treatment of idiopathic os odontoideum in children and compare these outcomes in age- and treatment-matched nonidiopathic children with os odontoideum.

METHODS

A retrospective multicenter review identified 102 children with os odontoideum, of whom 44 were idiopathic with minimum 2-year follow-up. Ten patients were treated conservatively, and 34 underwent spinal arthrodesis. Both groups were matched with nonidiopathic patients by age and type of treatment. Cervical arthrodesis was recommended for patients with increased atlantoaxial distance or reduced space available for the cord in flexion-extension radiographs.

RESULTS

All 20 children undergoing conservative treatment remained asymptomatic during follow-up, but 1 nonidiopathic patient developed cervical instability. The idiopathic group had significantly less severe radiographic cervical instability and less neurologic complications than the nonidiopathic group (P < 0.05 for all comparisons). Thirty-three (97%) patients in the idiopathic group and 32 (94%) patients in the nonidiopathic group (94%) had spinal fusion at final follow-up (P = 0.55). The risk of complications (15% vs. 41%; odds ratio 0.234, 95% confidence interval 0.072-0.757, P = 0.015) and nonunion (6% vs. 24%; odds ratio 0.203, 95% confidence interval 0.040-0.99, P = 0.040) were significantly lower in the idiopathic than in the nonidiopathic group. Idiopathic children undergoing rigid fixation achieved spinal fusion.

CONCLUSIONS

Idiopathic patients with stable atlantoaxial joint at presentation remained asymptomatic and intact during conservative treatment. Idiopathic children with os odontoideum undergoing spinal arthrodesis had significantly fewer complications and nonunion than nonidiopathic children.

LEVEL OF EVIDENCE

III.

Results of growth-friendly management of early-onset scoliosis in children with and without skeletal dysplasias

Aims

The aim of this study was to compare the surgical and quality-of-life outcomes of children with skeletal dysplasia to those in children with idiopathic early-onset scoliosis (EOS) undergoing growth-friendly management.

Patients and Methods

A retrospective review of two prospective multicentre EOS databases identified 33 children with skeletal dysplasia and EOS (major curve ≥ 30°) who were treated with growth-friendly instrumentation at younger than ten years of age, had a minimum two years of postoperative follow-up, and had undergone three or more lengthening procedures. From the same registries, 33 matched controls with idiopathic EOS were identified. A total of 20 children in both groups were treated with growing rods and 13 children were treated with vertical expandable prosthetic titanium rib (VEPTR) instrumentation.

Results

Mean preoperative major curves were 76° (34° to 115°) in the skeletal dysplasia group and 75° (51° to 113°) in the idiopathic group (p = 0.55), which were corrected at final follow-up to 49° (13° to 113°) and 46° (12° to 112°; p = 0.68), respectively. T1-S1 height increased by a mean of 36 mm (0 to 105) in the skeletal dysplasia group and 38 mm (7 to 104) in the idiopathic group at the index surgery (p = 0.40), and by 21 mm (1 to 68) and 46 mm (7 to 157), respectively, during the distraction period (p = 0.0085). The skeletal dysplasia group had significantly worse scores in the physical function, daily living, financial impact, and parent satisfaction preoperatively, as well as on financial impact and child satisfaction at final follow-up, than the idiopathic group (all p < 0.05). The domains of the 24-Item Early-Onset Scoliosis Questionnaire (EOSQ24) remained at the same level from preoperative to final follow-up in the skeletal dysplasia group (all p > 0.10).

Conclusion

Children with skeletal dysplasia gained significantly less spinal growth during growth-friendly management of their EOS and their health-related quality of life was significantly lower both preoperatively and at final follow-up than in children with idiopathic EOS. Cite this article: Bone Joint J 2019;101-B:1563–1569